Microcantilever-based techniques can be used to explore the autonomy and property of molecules (e.g. DNA and single actin filaments) adsorbed on a surface. A theoretical model is presented here to predict the resonance frequency of a cantilever induced by physically adsorbed atoms/molecules. The cantilever is modelled as a sandwich beam containing two surface layers of a finite thickness and a bulk layer between them. It is found that the resonance frequency shift depends sensitively on both the mass and bending stiffness variations of the cantilever induced by the adsorbed atoms/molecules. The adsorptions of O atoms on Si(1 0 0), of O atoms on Au(1 0 0) and of H atoms on Au(1 0 0) are taken as three representative examples. We demonstrate that physisorption can induce distinctly different resonant responses of cantilevers, depending not only on the adatoms but also on the substrate material. This study is helpful for the optimal design of microcantilever-based measurement techniques.

Microcantilever-based techniques can be used to explore the autonomy and property of biomolecules (e.g., DNA and single actin filaments) which, in measurement, are adsorbed on the cantilever surface. Here, an energy method is presented to predict the cantilever deflection induced by adsorbed atoms/molecules. The cantilever is modeled as a sandwich beam containing two surface layers of a finite thickness and a bulk layer between them. The adsorptions of O atoms on Si(100) and Hg atoms on Au(100) are taken as two representative examples. We demonstrate that physisorption can induce distinctly different deformation behaviors of cantilevers, which depend not only on the adatoms but also on the substrate material. These results are consistent with relevant experimental observations. This study is helpful for optimal design of microcantilever-based measurement techniques.

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CXCL12 and CXCR4 polymorphisms may be risk factors for HCC, and they may be potential HCC markers.

Hepatocellular carcinoma (HCC) is one of the most common malignancies in the world. The etiology and pathogenesis of HCC remain unclear. Macrophage migration inhibitory factor (MIF) plays a critical role in the pathogenesis of hepatocellular carcinoma. The association between MIF polymorphisms and its expression level in HCC has rarely been demonstrated. In the present study, the peripheral blood of 202 patients with HCC (HCC group), 242 patients with chronic hepatitis B (CHB group), 215 patients with liver cirrhosis (LC group) and 227 healthy volunteers (normal group) were collected, DNA was extracted and the target fragment of MIF gene was amplified using PCR. The products were then sequenced, and the expression levels of MIF protein were tested using ELISA. The results showed that the MIF rs755622 polymorphism was associated with an increased susceptibility and metastasis of HCC, and that the genotypes GC and CC were associated with poor prognosis of HCC. Compared with the normal, CHB and LC groups, the expression of MIF in the peripheral blood of the HCC group was significantly increased, and the high expression was associated with to poor prognosis. In the HCC group, MIF protein levels for genotypes GC and CC were increased compared with those of genotype GG. The current study indicated that the MIF rs755622 polymorphism is associated with susceptibility and metastasis of HCC, and that the GC and CC genotypes may be indicators of poor prognosis, which may be ascribed to the MIF rs755622 polymorphism leading to elevated MIF protein expression in peripheral blood.